package com.abc.encryption;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Base64;

public class AESUtil {
   private static final String KEY_ALGORITHM = "AES";
   private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";//默认的加密算法

   /**
    * AES 加密操作
    *
    * @param content 待加密内容
    * @param key     加密密钥
    * @return 返回Base64转码后的加密数据
    */
   public static String encrypt(String content, String key) {
      try {
         Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器

         byte[] byteContent = content.getBytes("utf-8");

         cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化为加密模式的密码器

         byte[] result = cipher.doFinal(byteContent);// 加密

         return Base64.getEncoder().encodeToString(result);//通过Base64转码返回

      }
      catch (Exception e) {
         e.printStackTrace();
      }

      return null;
   }

   /**
    * AES 解密操作
    *
    * @param content
    * @param key
    * @return
    */
   public static String decrypt(String content, String key) {

      try {
         //实例化
         Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

         //使用密钥初始化，设置为解密模式
         cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));

         //执行操作
         byte[] result = cipher.doFinal(Base64.getDecoder().decode(content));

         return new String(result, "utf-8");

      }
      catch (Exception e) {
         e.printStackTrace();

      }

      return null;
   }

   /**
    * 生成加密秘钥
    *
    * @return
    */
   private static SecretKeySpec getSecretKey(final String key) {
      //返回生成指定算法密钥生成器的 KeyGenerator 对象
      //返回生成指定算法密钥生成器的 KeyGenerator 对象
      KeyGenerator kg = null;

      try {
         kg = KeyGenerator.getInstance(KEY_ALGORITHM);

         //AES 要求密钥长度为 128
         kg.init(128, new SecureRandom(key.getBytes()));

         //生成一个密钥
         SecretKey secretKey = kg.generateKey();

         return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为AES专用密钥
      }
      catch (NoSuchAlgorithmException e) {
         e.printStackTrace();
      }

      return null;
   }

   public static void main(String[] args) {
      String content = "hello,您好";
      String key = "sde@5f98H*^hsff%dfs$r344&df8543*er";
      System.out.println("content:" + content);
      String s1 = EncryptUtil.getInstance().AESencode(content, key);
      System.out.println("s1:" + s1);
      System.out.println("s2:" + EncryptUtil.getInstance().AESdecode(s1, key));

   }
}
